The Eighteenth Century 163 



species of phosphorus, so called because it shines in the night, with- 

 out any light being thrown on it: such is the phosphorus made of 

 urine. . . . Mr. Boyle . . . gives an account of three Noctilucae— 

 The first, invented by Krafft, he calls the consistent, or gummous 

 Noctiluca, as being of a texture not unlike that of cherry-gum." It 

 was also called the constant Noctiluca or solid Phosphorus. 



The second is liquid, invented by the said Krafft, being only a dissolu- 

 tion of the former in a convenient liquor [oil]. The third kind was 

 prepared by Mr. Boyle himself, and of a different nature from both the 

 other; for it would not shine of itself, like either of them, but required 

 the contact of the air (though not any external rays or heat) ... it 

 was not the body that shown, but an exhalation or effluvium mixed 

 with the air; on which accounts, the inventor gives it the denomination 

 of the aerial Noctiluca. The same Mr. Boyle, afterwards, prepared 

 another sort; which from the little pellucid fragments, or crystals therein, 

 he denominated the icy Noctiluca. 



The word " luminescence " does not appear except in fairly recent 

 dictionaries. However, much discussion of luminescence is to be 

 found in the older encyclopedias under the heading " Luminosity " 

 or " Light." The word " Fire " may also contain data on lumines- 

 cence but Chambers merely gave an interesting discussion as to 

 whether fire is to be considered a body or a motion. 



Under the heading " Light," Chambers devoted two large pages 

 to the subject, quoting Newton on different ways of producing light 

 and referring to the experiments of Hauksbee on light from attri- 

 tion and rubbing and those of Boyle on shining wood and its be- 

 havior in a vacuum. Chambers also quoted M. Bernoulli who " found 

 by experiment that mercury amalgamated with tin and rubbed on 

 glass produced a considerable amount of light in the air; that gold 

 rubbed on glass did it still in a greater degree: but that, of all 

 others, the most exquisite light was that produced by the attrition 

 of a diamond." 



In a two-volume supplement ^' to the Cyclopedia, published in 

 1753 there is an additional three-page article on phosphori, bring- 

 ing the subject up to date. Data on light from rotten wood and 

 the experiments of Beccari are given. In the Chambers' treatment 

 of the subject bioluminescences occupy a subordinate place. In some 

 of the nineteenth-century encyclopedias this position is reversed and 

 a great deal of space is devoted to the " Luminosity of Animals and 

 Vegetables." However, we must conclude that the subject of lumi- 

 nescence was quite extensively considered in this Universal Dic- 

 tionary of Arts and Sciences. 



^'Abraham Rees (1743-1825) brought out an enlarged edition of Ephraim Chambers' 

 Cyclopedia in 1778-1788. 



